1. Field of the Invention
The present invention is directed in general to arthroplasty devices and, in particular, to arthroplasty devices which improve bone growth into said devices.
2. Description of the Related Art
The use of arthroplasty devices to replace damaged or defective joints within the body is commonplace in the medical field. The prosthetic replacement of joints has evolved over the years from early relatively crude models to current prostheses which closely replicate functions and motions of a natural joint. Prosthetic arthroplasty devices have been used as replacements for the shoulder, hips, knee, ankle and invertebral disc.
One problem encountered with prosthetic joints includes movement of the implant with respect to the patient's bones. This motion often compromises fixation. Another problem that occurs is an abnormal stress transference from the implant to the bone.
The most common method of holding the implant in the bones is “press-fitting” the device into the intramedullary cavity of the bone. This often causes abnormal stress distribution, leading to premature failure.
These devices also rely on the ingrowth of the patient's bone to hold these devices in place. The difficulty of achieving true growth of a patient's bone into a metal prosthesis is a well known problem in the surgical field.